Container shipment of goods has acquired widespread use because of reduced shipping costs and efficiency of movement. The containers can be easily transferred between different modes of transportation such as ship, rail and truck without the goods in the containers having to be transferred. For transportation of the containers overland, the loaded container is generally placed on a wheeled trailer frame commonly known as the chassis. A conventional over-the-road tractor may be hooked to the chassis to make up an articulated tractor-trailer truck for overland movement. The containers mounted on the chassis are also frequently moved by railroad flat car for overland movement.
It has become common practice for shipping companies to own fleets of these containers as well as the chassis for supporting the containers. Ocean shipping companies, however, do not usually perform overland transportation. As a result, they must provide their equipment, the containers and chassis, to inland carriers to accomplish the overland portion of the container and chassis movement. Often several inland carriers are involved in the overland portion of the movement. By way of example, a hypothetical illustration of the inland movement of a container/chassis combination from ocean port A to inland city B follows.
(I) The container is offloaded from an ocean going vessel onto the chassis at the ocean terminal in port A and the container/chassis combination is moved to a railroad terminal in port A by truck.
(II) The container/chassis combination is loaded onto a railroad flat car at the railroad terminal in port A and then transported to a regional city C in the vicinity of inland city B rail.
(III) The container/chassis combination is offloaded from the railroad flat car at the railroad terminal in regional city C and delivered to the ultimate receiver of the goods in inland city B by truck.
(IV) The emptied container/chassis combination is returned from the receiver in inland city B to a container storage yard in regional city C by truck.
(V) The empty container/chassis combination is picked up at the container storage facility in regional city C and moved by truck to a shipper's facility in regional city C where the container is reloaded for export.
(VI) The loaded export container/chassis combination is returned from the shipper's facility to the railroad terminal in regional city C by truck.
(VII) The loaded export container/chassis combination is placed on a railroad flat car at the railroad terminal in regional city C and transferred by train back to the railroad terminal in port city A.
(VIII) The loaded export container/chassis combination is picked up at the railroad terminal in port city A and transported to the ocean terminal in port city A by truck where the container is then offloaded from the chassis onto an ocean going vessel for shipment.
The fact that a container/chassis combination is handled by several different inland carriers presents little problem for the security of the cargo because the doors on the cargo container can be locked or sealed with a numbered seal in the same manner that the doors on an over-the-road tractor-trailer truck can be locked or sealed. This system works well because there exists a written interchange agreement between all of the inland carriers as well as the ocean carriers. These interchange agreements identify the seal numbers or locks on the container doors, the condition of the container when the inland carrier receives the container, the condition of the chassis when the carrier receives the chassis, and the per diem rental charges associated with the container and/or chassis. These interchange agreements are able to place the responsibility of the equipment on the carrier who has possesion of the equipment and can be used to pinpoint the particular inland carrier with which liability for damage or lost equipment can be attributed. Thus, if carrier A accepts an equipment interchange from carrier B, carrier A signs a receipt stating the condition of the equipment as well as the identification of the seal on the container doors if one exists. Thus, if carrier A accepted a container with Seal No. 10 on the container door and subsequently interchanged the equipment with no seal or a different seal on the container door, carrier A would be responsible to account for the change of seals and would be exposed to liability for a claim if there was a shortage of cargo.
While these interchange agreements have worked well with the container cargo as well as the container and chassis overall, the situation is more difficult to police under these interchange agreements when it comes to subparts of the equipment, particularly the tires on the chassis. At most interchange points, time and manpower does not permit careful inspection of the individual parts of the container and the chassis. A quick inspection confirms overall condition of the equipment and major damage can be easily noted. Current practice under these interchange agreements is not effective at controlling tire substitution on the chassis. Frequently, a chassis will leave the ocean shipper's facility with new tires and be returned after the inland portion of the journey with inferior replacement tires. This changes of tires is usually not spotted at the interchange points and, when the interchange of tires is actually spotted, it is often difficult to determine which inland carrier is responsible for the substituted tires, especially if the chassis has been interchanged several times. This same problem has also been experienced by all shipping companies that interchange equipment or lose possession of over-the-road wheeled equipment. Thus, the problem of tire substitution on wheeled equipment is experienced by all such equipment owners such as trucking companies, truck fleet owners, truck leasing companies, and shipping companies who own their own trailers as well as many other companies.
Various attempts have been made to solve this problem by providing some means to allow the trailer owner to quickly identify the tires that it places on the trailer. One of the problems with this practice is that access must be provided for the tires on the trailer frame or trailer to be removed at any time the wheeled equipment is in use so that the equipment tires can be changed as necessary in the event of a flat tire. The previous attempts at solving this problem have been relatively unsuccessful since they have not provided a sufficient indication to the equipment owner that the tires have been substituted when the equipment is returned.